The invention relates to textile carding machines and, in particular, to stop motion apparatus and condition responsive devices for detecting conditions of operation of the carding machine and for interrupting the drive motion of the carding machine in response thereto.
In a typical carding machine, a web or lap is processed in a carding operation to produce a sliver for subsequent processing into textile yarn. The lap is generally in the form of a web of textile material wound on a lap pin which is supported on the carding machine for unwinding and feeding to a main cylinder where it is carded. The textile material is removed from the carding cylinder by a doffer cylinder which rotates closely adjacent the carding cylinder on the end opposite the lap roll. The doffer cylinder is normally driven by a take-off from the main drive of the carding cylinder through a production gear. The production gear is engaged and disengaged with a ring gear mounted on the shaft of the doffer cylinder by means of raising and lowering a drop lever on which the production gear is carried. Other drive arrangements are also utilized. The lap roll is normally driven by a take-off from the doffer cylinder. The web of textile material removed by the doffer cylinder is subsequently drawn therefrom and condensed into a sliver which is deposited into a coiler can for transportation and further processsing. It is important that a uniform weight and quality of sliver be deposited in the coiling can.
During drawing of the sliver from the carding machine, breakage of the sliver often occurs in which case it is necessary to stop the drive motion of the carding machine.
Various devices have been heretofore proposed for sensing the weight of sliver and the breakage of sliver as it is delivered from the carding machine to the coiler can and for stopping the card in response thereto. U.S. Pat. No. 3,270,374 discloses a card stop motion wherein compressed air is utilized to shift a drive belt from a drive pulley to an idler pulley to stop the card in response to the detection of certain sliver conditions. U.S. Pat. No. 3,191,236 shows a mechanical stop motion for a card which utilizes a sliver sensing rod for mechanically actuating a linkage assembly which, in turn, actuates the drop lever of the carding machine which engages and disengages a production drive gear. U.S. Pat. No. 3,199,151 discloses an electro-mechanical stop motion device for a cotton card wherein the sliver is passed through an eye of a pivotable sliver sensing rod which actuates a solenoid in response to sliver breakage. The solenoid withdraws a pin from a notch formed in a spring-loaded plunger releasing the spring-loaded plunger to rotate a belt shifting fork to cause a drive belt to be shifted from a drive pulley to an idler pulley. However, the linkage assembly of the above mechanical devices often are insensitive to the detection of sliver conditions and are easily made unresponsive when the various linkage elements become bent or out of adjustment.
Another condition to which attention need be given in operating a carding machine is the condition of the lap roll. It is desirable to stop the motion of the carding machine and not feed the tail end of the lap to the carding cylinder. The tail end of the lap is normally quite different in its physical characteristics and often includes a double lap of material which, if fed to the main carding cylinder, can result in damage to the clothing of the main cylinder as well as produce inferior sliver if carded. U.S. Pat. No. 3,462,798 discloses a pivotal lever which detects the vertical movement of the lap pin in order to stop the card before the tail of the lap is fed. However, the pivotal lever pin easily becomes bent out of adjustment stopping the card prematurely or not at all. Such is also highly susceptible to abuse by the machine operator who bends it out of shape so as not to be bothered by its maladjusted operation.
Another condition to which considerable attention need be given is the condition of the doffer cylinder. Lap-up of a web material about the doffer cylinder can occur resulting in damage to the metallic clothing of the doffer cylinder and main carding cylinder and physical injury can result if the hands of the operator are caught between the doffer cylinder and doffer shield in attempting to prevent lap-up.